public onToolboxItemDragStart(event: DragEvent, toolboxItem: ToolboxItem): void {
        console.log('onToolboxItemDragStart: ' + JSON.stringify(toolboxItem));

        const uA = window.navigator.userAgent,
            onlyIEorEdge = /msie\s|trident\/|edge\//i.test(uA) && !!((<any>document).uniqueID || (<any>window).MSInputMethodContext),
            checkVersion = (onlyIEorEdge && +(/(edge\/|rv:|msie\s)([\d.]+)/i.exec(uA)[2])) || NaN;

        if (onlyIEorEdge) {
            html2canvas(event.target, {
                onrendered: (canvas) => {
                    let dragStylesCSS,
                        dragStylesEl,
                        headEl,
                        eventTarget;
                    // generate a random class name that will be added to the element
                    let randomDraggingClassName = 'setdragimage-ie-dragging-' + Math.round(Math.random() * Math.pow(10, 5)) + '-' + Date.now();
                    // prepare the rules for the random class

                    dragStylesCSS = [
                        '.' + randomDraggingClassName,
                        '{',
                        'background: url("' + canvas.toDataURL('image/png') + '") no-repeat #fff 0 0 !important;',
                        'width: ' + canvas.width + ' !important;',
                        'height: ' + canvas.height + ' !important;',
                        'text-indent: -9999px !important;',
                        'border: 0 !important;',
                        'outline: 0 !important;',
                        '}',
                        '.' + randomDraggingClassName + ' * {',
                        'display: none !important;',
                        '}'
                    ];

                    // create the element and add it to the head of the page
                    dragStylesEl = document.createElement('style');
                    dragStylesEl.innerText = dragStylesCSS.join('');
                    headEl = document.getElementsByTagName('head')[0];
                    headEl.appendChild(dragStylesEl);

                    /*
                    since we can't get the target element over which the drag start event occurred
                    (because the `this` represents the DataTransfer object and not the element),
                    we will walk through the parents of the current functions until we find one
                    whose first argument is a drag event
                     */
                    eventTarget = event.target;
                    // and add the class we prepared to it
                    eventTarget.classList.add(randomDraggingClassName);

                    /* immediately after adding the class, we remove it. in this way the browser will
                    have time to make a snapshot and use it just so it looks like the drag element */
                    setTimeout(function() {
                        // remove the styles
                        headEl.removeChild(dragStylesEl);
                        // remove the class
                        eventTarget.classList.remove(randomDraggingClassName);
                    }, 0);
                }
            });
        }

        event.stopPropagation();

        if (!this.currentSeatingChart) {
            return;
        }

        let chartObject = Helpers.clone(toolboxItem.object);
        chartObject._id = Helpers.newGuid();
        chartObject.chart = this.currentSeatingChart._id;

        let maxNumber = 1;
        if (this.currentChartObjects.length) {
            maxNumber = this.currentChartObjects[this.currentChartObjects.length - 1].sequenceNumber;
            if (!maxNumber) {
                maxNumber = 0;
            }
            maxNumber += 1;
        }

        chartObject.sequenceNumber = maxNumber;

        this.draggedChartObject = chartObject;

        try {
            let chartItemConfig = ChartObjectFactory.createChartItemConfig(chartObject);
            event.dataTransfer.setData('text', JSON.stringify(chartItemConfig));//'seating-chart-object'
        } catch (e) {
            console.error(e);
            throw e;
        }
    }